verb / noun
simmer
SIM-er/ˈsɪmər/
To remain hot just below a full boil.
The soup simmers over a low flame, with tiny bubbles at the edges.

Etymology
Middle English simperen might have imitated a sound. Simmer originally described the gentle hissing of liquid beginning to boil, connecting that sound with cooking just below boiling.
In context
cook this for about three to five minutes until the onion has softened and then we just add in our sauce let it simmer for about 10 minutes
More examples
- Keep the sauce at a simmer for ten minutes.
- Simmer the beans until they are tender.
- The broth is simmering, not boiling.
Forms
simmer · simmers · simmered · simmering